The potential for manipulating cells to repair or replace diseased or damaged tissue has generated a great deal of excitement amongst scientific, medical and biotechnology community.
Current cell based therapies have the potential to generate replacement cells for a broad array of tissues and organs such as skin, cornea, cartilage and other kinds of tissues that require the delivery of their cells to the site of transplantation. This is feasible by growing the cells either as monolayers on suitable membranes (U.S. Pat. No. 5,693,332 specifically incorporated herein by reference) and/or differentiating into multi layers (US patent No. 2003/0208266A1 specifically incorporated herein by reference) before transplantation, or culturing the cells on foams or sponges which can then be transplanted. Several membranes including but not limited to amniotic membrane, polyurethane films are used for culturing cells, which are then transplanted on the patient. To the best of knowledge of the inventors, none of the commercially available inserts have a provision to use membranes of choice. This restricts the use of such commercial inserts as a choice for membrane based delivery of cells.
Currently, under laboratory conditions, the membranes meant for cell support and transplantation are cultured in tissue culture dishes. The membranes are held flat and taut using metallic rings. Transportation of these cultures per se in such dishes is not feasible because of their design which provides for air exchange and hence does not ensure leak proof transportation. Media spillage not only wastes the precious media but also increases the chances of contamination. It is desirable before transplantation, for safety reasons, that the cultures be rinsed with a buffered solution to ensure the removal of traces of the transport media which might contain harmful substances like DMSO, which is used for cryopreservation; or proteins of animal origin present in the transport media. Rinsing of membranes by direct addition of the wash buffer to the cells present on the membrane would result in some of the cells getting detached from the membrane.
Traditional culture vessels generally have a circular shape and can be either single dish or multiple dishes. U.S. Pat. No. 4,349,632 discloses a tissue culture cluster dish having different numbers of wells.
U.S. Pat. Nos. 4,871,674A and 5,026,649 describe cell culture inserts for culturing membranes. The aforesaid devices have the following disadvantages. For example, these inserts have a fixed membrane upon which cell attachment, growth and differentiation occurs. Since the membranes are fixed, it is not possible to use any other membranes of choice for culturing cells. Besides, these membranes can be removed from the insert only after cutting with scalpel, which might result in damage to the cells. The available inserts, meant for culturing cells in multiwell dishes are of small sizes and not suitable for culturing cells in large areas. The membranes available in these inserts are not indicated for transplantation, thereby restricting their use to only culturing cells.